1. Technical Field
The present invention relates to potassium titanate, a manufacturing method thereof, a friction material containing the potassium titanate and a resin composition containing the potassium titanate.
2. Description of Related Art
Potassium titanate fiber, which is not a cancer-causing substance such as asbestos, has been widely used as a friction modifier, chiefly for incorporation in a vehicle brake pad. A friction material containing such potassium titanate fibers has a very favorable advantage that it causes no damage to a brake disk while exhibiting an excellent sliding property and a good braking effect.
However, the potassium titanate fibers, because of their fibrous form, present the following problems: they are bulky; they exhibit poor flowability; and they tend to get stuck on a wall of a feed passage during manufacture to eventually block it. In order to solve such problems, potassium titanate having a sheet or plate form, such as potassium octatitanate, potassium hexatitanate or potassium tetratitanate, has been proposed (see, for example, Japanese Patent Laid-Open Nos. 2001-106526 and 2001-253712).
However, there remains a need for further improvements in terms of wear resistance of a friction modifier, particularly in a high-temperature range.
In Japanese Patent Laid-Open No. 2000-256013, potassium titanate fine particles are proposed which have a major diameter of less than 5 μm. Although these potassium titanate fine particles exhibit a low X-ray diffraction intensity and show a diffraction line with a large half width, their friction and wear characteristics have been insufficient.